Unsolved mystery: Songbirds stop dying, but what killed them? And could it resurge next spring?


YORK COUNTY, Pa. (WHTM) — Whatever killed at least 3,500 reported songbirds throughout all 67 Pennsylvania counties — and likely caused countless other unreported deaths — went away late summer about as suddenly and mysteriously as it arrived during late spring.

First, the good news — and there’s actually a lot of it:

After a precipitous decline in August of reports of diseased-looking, wobbly birds with swollen eyes, “People have put their bird feeders back out, and we haven’t seen a resurgence of problems,” said Dr. Lisa Murphy, co-director of the Wildlife Futures Program at the University of Pennsylvania School of Veterinary Medicine and an associate professor of toxicology.

Murphy also said the infrastructure that emerged to facilitate collaboration between her organization, the state’s game commission, local wildlife rescue organizations, and concerned members of the public will benefit future investigations.

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The admonition by wildlife officials to remove bird feeders and birdbaths was to prevent birds from congregating, in case whatever was willing them was contagious.

But “we investigated various infectious, bacterial, viral diseases and were actually very happy that all of those tests came back negative,” Murphy said. “However, it didn’t really give us an answer of what was going on with those birds.”

Another theory among others: something to do with the Brood X 17-year cicadas. Maybe the cicadas were eating something toxic, like pesticides, and the birds were eating the cicadas. The timing made sense, and insects make up a bigger portion of the diets of young birds — which seemed to be dying at particularly high rates — than of older ones.

But again, the investigators “just didn’t come up with anything particularly consistent or conclusive,” Murphy said.

And that’s where the investigation stands. Murphy and her colleagues are glad tests were negative for their worst fears, and they’re especially glad the problem has subsided — for whatever reason — even if the uncertainty is “as unsatisfying for us doing the diagnostics as it is for the general public,” Murphy said.

“We like to do what we do [because] we like to try to answer those tough questions,” she said. “It’s like detective work. And sometimes it can be frustrating when we don’t automatically get answers or all the answers that we’re looking for.”

Investigators will feel better if next June and July come and go without a resurgence because no one knows for sure if the decline in cases is related to the decline in numbers of fledgling birds this time of year, several months removed from nesting season.

“Once they sort of age out of that, were they no longer susceptible? Have the birds that were capable of recovering done so and literally have moved on with their lives?” Murphy said, characterizing the questions that linger.

As for anyone should do if they see a diseased-looking bird or other wildlife anomalies?

“It almost sounds cliché in this day and age, but when you see something, say something,” Murphy said. Specifically, she said to contact:

One of those local wildlife rehabilitators is Emily Garrigan, founder, and certified wildlife rehabilitator at West Shore Wildlife Center in Etters, York County. She has eight songbirds at the center right now — but all for other issues. An outdoor enclosure held two morning doves, both with wing injuries; Garrigan said she hoped to be able to release them back into the wild within about a week.

Garrigan agreed that the avian issue — whatever it was — brought out the best in a lot of humans.

“It was really cool to see people that care, and that they would call in, in case this does ever happen in the future,” she said.

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